Straw Hat Day, celebrated on May 1st, marked the unofficial start of summer for men, as it was the day they could finally don their summer hats. This tradition held significance, as it symbolized the seasonal shift and the embrace of warmer weather. The observance of this day became a cultural norm, with men eagerly participating in this lighthearted fashion rule.

In Erik Larson's "Dead Wake: The Last Crossing of the Lusitania," the mention of Straw Hat Day reflects societal customs of the early 20th century. It highlights the everyday life and cultural practices of that era, setting the context for the events surrounding the Lusitania's fateful journey. Such details enrich the narrative, providing readers with a glimpse into the fashion and social practices that defined the time.